Pioneer 9 Spacecraft Instrument Host Overview ======================== Pioneer 9, also known as Pioneer D, was the fourth in a series of solar-orbiting, spin-stabilized, and solar-cell- and battery-powered satellites designed to obtain measurements of interplanetary phenomena from widely separated points in space on a continuing basis. The spacecraft carried experiments to study the positive ions and electrons in the solar wind, the interplanetary electron density (radio propagation experiment), solar and galactic cosmic rays, the interplanetary magnetic field, cosmic dust, and electric fields. Also, a new coding process for transferring data from the spacecraft to the Deep Space Network was implemented for Pioneer 9. The main antenna for Pioneer 9 was a high-gain directional one. The spacecraft was spin-stabilized at approximately 60 revolutions per minute, with the spin axis perpendicular to the ecliptic plane and pointed toward the south ecliptic pole. By ground command, one of five bit rates, one of four data formats, and one of four operating modes could be selected. The five bit rates were 512, 256, 64, 16, and 8 bits per second. Three of the four data formats contained primarily scientific data and consisted of 32 seven-bit words per frame. One scientific data format was used at the two highest bit rates, another was used at the three lowest bit rates, and the third contained data from only the radio-propagation experiment. The fourth data format contained mainly engineering data. The four operating modes were real-time, telemetry-store, duty-cycle store, and memory readout. In the real-time mode, data were sampled and transmitted directly (without storage) as specified by the data format and bit rate selected. In the telemetry-store mode, data were stored and transmitted simultaneously in the format and at the bit rate selected. In the duty-cycle store mode, a single frame of scientific data was collected and stored at a rate of 512 bits per second. The time interval between collection and storage of successive frames could be varied by ground command between 2 and 17 minutes to provide partial data coverage for periods of up to 19 hours, as limited by the bit-storage capacity. In the memory readout mode, data were read out at whatever bit rate was appropriate to the satellite distance from the Earth. Pioneer 9 was launched on 08 November December 1968 into a 297.6-day heliocentric orbit with radii of 0.75 x 0.99 AU and an inclination of 0.086 degrees. Mission controllers maintained contact with Pioneer 9 until 19 May 1983. Controllers made an unsuccessful attempt in March 1987 to contact the spacecraft. NASA declared the Pioneer 9 inactive at that time. Facts in Brief ============== Mission Type: Orbiter Launch Date: 1968-11-08 at 09:46:00 UTC Launch Vehicle: Thor-Delta E-1 (no. 60 / Thor no. 479 / DSV-3E) Launch Site: Cape Canaveral, USA / launch complex 17B NASA Center: Ames Research Center Mass: 147.0 kg Spacecraft Instruments and Principal Investigator: Tri-axial Fluxgate Magnetometer, Charles Sonett Solar Plasma Detector, John Wolfe Two-Frequency Beacon Receiver, Von Eshleman Cosmic Dust Detector, Otto Berg Cosmic-Ray Anisotropy Experiment, Kenneth McCracken Cosmic-Ray Gradient Detector, William Webber Electric Field Detector, Frederick Scarf Celestial Mechanics Experiment, John Anderson Spacecraft Power: Solar cells and batteries Maximum Data Rate: 512 bits per second NSSDCA/COSPAR Spacecraft ID: 1968-100A References ========== Siddiqi, A.A., Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, Monographs in Aerospace History No. 24, NASA, SP-2002-4524, Washington, D.C, 2002.